Explanation of Plates. 105 



PLATE VI. 



•PAGE. 



Fig. i. Sphenophyllum vetustum, Newb., 55 



Branch with branchlets and leaves. Natural size. 



Corniferous Limestone, Delaware, Ohio. 

 Fig. 2. Lepidodendron gaspianum, Dawson, 56 



Detached branch, showing leaves and leaf scars. Natural size. 



Corniferous Limestone, Delaware, Ohio. 

 Fig. 3. Dadoxylon newberryi, Dawson, 53 



Radial section of wood, showing portion of medullary ray with clus- 

 ters of areoles. 

 Fig. 3a. Transverse section of portion of trunk. 

 Fig. 3b. Tangential section of same. All much magnified. 



Huron Shale, Delaware, Ohio. 



